What if you were to learn that your horse is living with a hidden malformation? A skeletal abnormality that could be affecting it every day, changing the way it moves, creating a string of other physical problems, and possibly underlying the hard-to-pinpoint problems you’ve been noticing for months or even years ?

And that might even be causing a level of inherent instability that could be putting the rider in danger?

Sadly, this isn’t a hypothetical question. Instead it’s a reality that is only now being slowly uncovered.

And like the proverbial stone rolling down a mountain, the issue is gathering momentum as the equine industry, owners, breeders and researchers learn about it.

It’s a skeletal malformation and it can’t be corrected.

It’s congenital, ie inherited, so is present from birth.

It has been in some lines of TBs for hundreds of years.

It creates biomechanical issues due to asymmetry and lack of anchor points for key muscles.

At its worst, it can contribute to neurological issues such as Wobbler syndrome.

Some horses are so unstable, they are more prone to falling (not good news for jockeys).

It can cause constant pain and associated behavioural changes.

It’s primarily found in Thoroughbreds, Thoroughbred crosses and Warmbloods, but has also been identified in European breeds, Quarter Horses, Arabs and Australian Stock Horses.

The problem behind this is a congenital malformation of the C6 and C7 cervical vertebrae (ie, base of neck) – and it’s pretty nasty.

I’ve written about the work of Sharon May-Davis on this blog before and here I’m going to do so again. Through her many dissections per year, gross anatomist Sharon has become the first person to comprehensively document and quantify this problem.

In doing so, and publishing her findings in peer-reviewed journals, she has triggered a minor research avalanche as others take up the subject.

Those of us fortunate to attend Sharon’s many equine dissections in Australia, New Zealand, Japan, and Europe have been learning about this for some time. For bodyworkers and hoof trimmers, it has dramatically changed our work. I believe I’ve worked on several horses with this problem, including an eventing horse, a dressage prospect, and a TB intended for a child.

It is, not to put too fine a point on it, an extremely serious problem that is in some cases grave for the horse concerned and can potentially cause injury or loss of life for the rider.

The following is an amended version of an article that I wrote for the Winter 2017 edition of Equine News, a NSW, Australia print magazine that sponsored one of Sharon’s series of public lectures on this issue.

A hidden problem: this OTTB had the C6-C7 malformation but presented few outward signs.

Twenty years of research

Sharon May-Davis’s path with this research began some 20 years ago. In February 1996, a Thoroughbred called Presley came down unimpeded in a race in Grafton, NSW, fracturing his pelvis, a hock bone, and right front fetlock.

Three years later, Sharon examined his bones, and saw something strange in his last two cervical vertebrae and his first ribs.

Fast forward to 2014, when Sharon published the first of her four peer-reviewed papers in the Journal of Equine Veterinary Science, concerning a congenital malformation in the sixth and seventh cervical (neck) vertebrae.

Although the problem had been mentioned briefly in papers, this was the first time that a researcher had accurately described and quantified the problem in its various forms.

Sharon’s unique perspective, gained as an anatomist who dissects between 15 and 20 horses per year, had certainly placed her in a position to do so.

The horse’s seven cervical vertebrae – made simple

Horses have seven vertebrae in their necks, labelled C1 to C7. Of these, four have unique shapes. Most horse people are familiar with C1, the first vertebrae known as the atlas, as it can be both seen and felt by hand with its distinctive ‘wing’ at the top of the neck.

Both atlas and axis have unique shapes for a special reason: they support the heavy skull and anchor the muscles that control the head’s movement.

Heading down the neck, C3, C4 and C5 are broadly similar in shape, with each being a bit shorter and blockier than the one above.

However, C6 and C7 are both slightly different on the ventral (lower) side, for here they provide insertion points for muscles arising from the chest.

C6 has transverse processes (the protrusions extending outwards) that are different to those of neighbouring bones, with two distinctive ridges running the vertebrae’s length. C6 also has two large transverse foramen, the openings that the arteries pass through.

C7 is the shortest and squattest cervical vertebrae of all. Its transverse processes are shorter, while there are also two facets that articulate with the first ribs. C7 has no transverse foramen.

At least, that’s how the vertebrae should be in a normal horse.

So, what is wrong with the malformed C6 and C7 vertebrae?

In certain horses, these last two vertebrae are rather different, being malformed.

Sharon has identified the manifestations of this problem as a congenital (inherited) malformation affecting some Thoroughbred horses, and horses with Thoroughbred blood in their ancestry.

In C6, there is a problem with the two ridges of the transverse processes, as one or both can be partially absent.

When both are partially missing, it is common for one or two ridges (ie, parts of the transverse processes) to appear on C7 instead.

Also, the articular processes (the oval surfaces on the upper side, where each vertebrae links to its neighbours) can be radically different sizes. There can also be an additional arterial foramen or two.

The level of asymmetry can be radical.

The secondary problems this malformation causes

Being at the base of the neck, the asymmetry of C6 and C7 can cause alignment problems all the way up the vertebral column, leading to osteoarthritis of the articular facets.

It can also contribute to Wobbler Syndrome (Cervical Vertebral Stenotic Myelopathy), due to narrowing and/or malalignment of the vertebral foramen/canal, the opening through which the spinal cord passes. Not all Wobbler cases have this particular malformation, though.

A further problem is that the lower part of the longus colli muscle, which is involved in flexing the neck, would normally insert on the transverse processes of C6 and C7. When these processes are malformed, the normal insertions are not possible.

This means there is a serious symmetry problem in the junction of the thorax and neck, which can have a deeper effect on the horse’s neurology and proprioception, as well as respiration.

In a few cases, horses with both the C6 and C7 problem also have malformations of the first sternal rib, on one or both sides. This can cause problems beneath the scapular and further issues with muscular attachments.

Associated stability problems can have far-reaching consequences for the horse, not to mention some serious safety issues for the rider. The safety issue can’t be stated often enough.

Why isn’t the C6-C7 problem more widely known ?

Why hasn’t this problem been noticed in regular veterinary interventions?

The answer is quite simple. While neurological issues may have been diagnosed, the exact cause has often remained hidden.

Both Thoroughbred horses and Warmbloods are known to have higher incidences of Wobbler Syndrome than other breeds, and while this is certainly not always due to C6-C7 malformation, the malformation has been found in some when dissected.

For example, the following dissection image appears in a veterinary account of large animal spinal cord diseases. It clearly shows a malformed C7 vertebrae, very similar to the one in the above image, but without giving any further categorisation.

The difficulty lies in the deep location of the lower cervical vertebrae. While normal radiographs can show all or some of C6, they are unable to penetrate the deeper tissues beneath the shoulder to image C7.

Photo from another online article: the familiar asymmetry of a malformed C7 is clearly visible in a dissected set of vertebrae. (c) veteriankey.com (click image to access full article.)

Nevertheless, the malformation can be identified in radiographs of C6, once you know where to look.

Since Sharon’s first paper appeared, the School of Veterinary Medicine, University of California, Davis, has reviewed its history of radiographs from horses with Wobbler Syndrome.

Is this rare, or are many horses affected?

While the problem has been identified primarily in TBs, it affects most breeds with TB blood in the ancestry to some degree.

Sharon May-Davis reports that to date, published, peer-reviewed journal papers have tallied 136 out of 471 horses as exhibiting congenital malformation of C6.

These have been in a range of breeds including Thoroughbreds (39%), Thoroughbred crosses (27%), Warmbloods and European breeds (30%), Quarter Horses (11%), and Arabs (11%). Standardbreds have also shown the problem, although the numbers included in studies are very small.

A common question is whether it’s known which TB lines predominantly carry this problem. The answer is: Yes. However, it is now so disseminated amongst the modern equine population beyond TBs, that it is of little help to identify them.

“Eight Belles… might have been genetically predisposed to breaking down.”

It must be remembered that these horses are those already brought to veterinary attention and/or euthanized for a related or unrelated reason, so the percentages may be higher than those for the general horse population. At the same time, the malformation might have played a major part in the horses’ decline, due to the many locomotory and postural problems it can lead to.

‘Gift Horse’, the Trafalgar Square sculpture by Hans Haacke, displayed the malformation, presumably having been modelled on a modern-day skeleton. The George Stubbs anatomical drawing on which it was styled did not. Image (c) bowlofchalk.net

How do we identify these horses in life?

It’s all very well looking at these bones post mortem, you might say. Yet how can I tell if my horse has this problem? Or a horse that I might want to buy?

Some answers are forthcoming. As Sharon has frequently assessed horses before dissecting them – usually from video – she has been able to observe that many of these horses lack stability. (Indeed, in many cases, it is this very instability has directly led to the horse being euthanized, and ending up on the dissection table.)

As her research has progressed, she has also been able to identify many biomechanical and locomotion traits that make these horses ‘suspicious’ or at least ‘of interest’. Unsurprisingly, these problems have been particularly noticeable in horses with both a malformed C6 and C7.

For owners and equine professionals, here are some signs that can raise initial suspicions. All can also be caused by other problems, so a group of signs is more common than an individual indication.

Some of these horses have a problem with standing square in front, and will always keep one foot further forward. This can persist despite all attempts to improve the horse’s body and to train the horse to halt squarely.

Horses with the more serious malformations will often stand base-wide. Such horses can become very unbalanced on uneven ground, and sometimes in work. They easily become unbalanced when a hoof practitioner works on a forefoot.

A bilateral C6 – unilateral C7 horse showing a toe-out stance and hoof distortion. The ventral part of the transverse process was transposed onto the left side of C7.

With such asymmetry in the skeletal structure, these horses have serious lateral flexion issues that can’t be overcome. When required to elevate the forehand, many will experience difficulties, due to the absence of correctly inserted musculature and incorrect articulation through the joints of the lower neck.

The horse may have one very prominent, widely positioned scapula.

A high level of asymmetry may be seen in the shoulders, with one scapula sometimes positioned very wide, with no improvement after chiro, osteopathy or bodywork. This is particularly so with the C6-C7 problem and associated first sternal rib abnormalities.

The ventral aspect of the neck may show some scoliosis.

There may be scoliosis along the entire spine.

There may be an obvious scoliosis to the underside of the neck.

The problem may lead to heavily asymmetric loading of the forefeet, so may be accompanied by a severe high foot/low foot issue (this is not in itself a sign of the C6-C7 problem).

If you suspect your horse has the C6-C7 issue

First, note that many horses do just fine with a C6 problem. It is those with the bilateral C6 and unilateral/bilateral C7 issue that tend to show the more worrying problems.

If your horse is showing ongoing signs of instability, it’s important to seek veterinary advice, so that neurological issues can be ruled out. (As this a recently recognised problem, it may be worth printing out the abstracts from the journal articles listed at the end of this page and handing them over.)

If the more severe malformations are identified by radiograph, it is important to remember that in some cases this can cause discomfort and pain to the horse, and it is not going to improve over time.

On the contrary, the cervical vertebrae of some older horses with the C6 and C7 malformations often display advanced osteoarthritis of the articular processes, as shown in the header image of a 19-year-old Thoroughbred’s malformed C7.

Where does this knowledge take us?

At the moment, that question is wide open. The findings published by Sharon May-Davis have triggered ongoing research on an international level. There are certainly ramifications for breeders in more than one equine sporting industry.

Connections have been made with a number of falls on the racetrack that have caused injury, and worse, to both horse and jockey, as well as other runners. Similar things can be said for the sport of eventing, where unforced errors can have equally catastrophic effects.

It is entirely possible that at higher levels, pre-purchase examination radiographs will come to include a check on C6. While it’s not possible to radiograph the deeply positioned C7, we do at least know that this will only be present if the C6 anomaly exists.

Vets in some countries are proving faster at picking this up than others. While papers are being published, it clearly takes some time for information to filter down.

And until more is known, this problem is being unknowingly propagated every breeding season.

Of course, many horses harbouring the milder manifestations of this problem at C6 level are functioning very well. All horse owners can do is be aware that this issue exists, make use of this information if a problem arises, and await further research findings.

It’s barely mentioned in saddle fit or anatomy books, yet M. spinalis cevicis can hugely impact on the spinal health and movement of the horse, particularly with poor tack fit.

Meet M. spinalis cervicis et thoracis, a far more important muscle than is generally realized. As a deep muscle, it’s influential in mobilizing and stabilizing that hidden area of the spine at the base of the neck, the cervico-thoracic junction, deep between the scapulae.

Where to Find this Muscle

As part of the deeper musculature, M. spinalis is as hidden in books as it is in life. Usually, it’s a single entry in the index.

At best, it has no more than a bit part in anatomical illustrations, usually as a small triangular area at the base of the withers. This is also where we can palpate it.

The reality is quite a bit more interesting. It’s actually a muscle of three parts – dorsalis, thoracis and cervicis. These names denote its many insertions,
for it links the spinous processes of the lumbar, thoracic and cervical vertebrae.

Further back along the spine, it lies medially to the M. longissimus dorsi, and in fact integrates with this larger, better known muscle, attaching to the processes of the lumbar and thoracic vertebrae.

When it reaches the withers, it becomes more independent, attaching to the processes of the first half dozen thoracic vertebrae (T1-T6). Here, the cervical and thoracic portions overlap and integrate to share a common attachment. (The part we palpate, at the base of the withers, is the thoracic section.)

Heading into the neck, as M. spinalis cervicis, it attches to the last 4 or 5 cervical vertebrae (C3/C4-C7). Only the lamellar portion of the nuchal ligament runs deeper than this muscle.

Its integration with other muscles is complex, and its close relationship with M. longissimus dorsi partially explains why it doesn’t get much consideration as a muscle in its own right.

It is the more independent section, M. spinalis cervicis, between withers and neck, that we are interested in, although its influence is present along the entire spine.

What Does Spinalis Do?

In his 1980s’ Guide to Lameness videos, Dr. James Rooney, first director of the Gluck Equine Research Center, University of Kentucky, referred to M. spinalis as part of the suspension bridge of muscles supporting the spine (M. longissimus dorsi achoring from the lumbosacral vertebrae, M. spinalis thoracis et dorsalis from the upper thoracics). He also refers to this extensively in The Lame Horse (1988).

In fact, the suspension bridge analogy only really makes sense if M. spinalis dorsi is considered.

M. spinalis cervicisis usually credited with a role in turning the head to left to right, and raising the head.

Older texts, such as Bradley’s 1922 veterinary dissection guide, Topographical Anatomy of the Horse, mention its role in stabilizing the spine.

This creates a point of interest. Given that the nuchal ligament (lamellar portion) doesn’t attach to C6 and frequently only weakly with C5 (see the findings of anatomist Sharon May-Davis, in this earlier article ), M. spinalis cervicis suddenly appears pretty important in stabilizing and lifting the base of the neck, particularly as it does so at the point of greatest lateral bending.

ETA: Having now talked to Sharon, it appears that in her dissections, she has made a finding about an association between the lamellar portion of the nuchal ligament and M. spinalis. I’ll be writing an update article on this in February. [added 3 Jan 2017]

Spinalis and Poor Saddle Fit

Anyone who has been involved in close examination of the horse’s back will recognize M. spinalis thoracis where it surfaces close to the skin, on either side of the withers.

When a horse has been ridden in an overly tight saddle, this small area of muscle can become pretty hypertrophic – raised and hardened. Typically, the neighbouring muscles are atrophied. When M. spinalis is palpated, the horse often gives an intense pain response, flinching down and raising the head.

What often happens is this. An overtight saddle fits over the base of the withers like a clothes peg, pinching M. trapezius thoracis and M. longissimusdorsi. However, it frequently misses M. spinalis thoracis where it surfaces, wholly or partially within the gullet space. Often, the muscle is partially affected.

It’s as if the neighbouring muscles are under lockdown. Free movement of the shoulder is restricted and the horse’s ability to bear weight efficiently while moving is impeded. In response to the surrounding restriction and its own limitation, this muscle starts to overwork.

Result? The horse, which was probably already moving with an incorrect posture, hollows its back even further, shortening the neck and raising its head. As this becomes even more of a biomechanical necessity, all the muscles work even harder to maintain this ability to move, despite the compromised biomechanics.

Working harder and compensating for its neighbours, M. spinalis becomes hypertrophic. It is doing what it was designed to do, but it’s now overdoing it and failing to release. We now have a rather nasty vicious circle.

Here, M. spinalis thoracis stands out due to atrophy of the surrounding musculature. In this TB, a clearly audible adjustment occurred in the C4-C5 area after M. spinalis was addressed.

The Inverted Posture and Asymmetry

Of course, saddle fit is not the only cause of an inverted posture. However, any horse that holds its head and neck high for natural or unnatural reasons is more vulnerable to saddle fit issues, thus starting a cascade effect of problems.

Are there further effects of this hypertrophy? Consider the connections.

When saddles are too tight, they’re often tighter on one side than the other. This can be due to existing asymmetry in the horse, such as uneven shoulders, uneven hindquarters, scoliosis, etc.

On the side with greater restriction, the muscle becomes more more hypertrophic.

With its attachment to the spinous processes of the lower cervical vertebrae, there is an unequal muscular tension affecting the spine.

Without inherent stability, the neck and head are constantly being pulled more to one side than the other, with the lower curve of the spine also affected.

Base of neck asymmetry affects the rest of the spine in both directions and compromises the horses ability to work with straightness or elevation.

There is also asymmetric loading into the forefeet.

We haven’t even started looking at neurological effects…

This isn’t speculation. I have seen this pattern in horses I’ve worked on, many times over.

So, How Do We Help?

In working with saddle fit problems, the saddle refit may be enough to help the horse, if the riding is appropriate to restoring correct carriage and movement. Obviously, the horse’s musculoskeletal system is complex and no muscle can be considered in isolation. As other muscles are addressed through therapeutic training approaches, with correct lateral and vertical flexion achieved, M. spinalis will be lengthened along with the surrounding musculature.

I hold with a restorative approach:

Refit the saddle,preferably with the help of a trained professional,

Remedial bodywork, to support recovery from the physical damage,

Rest the horse,to enable healing of damaged tissue and lowering of inflammation, and

Rehabilitate the horse, through the appropriate correct training that elevates the upper thoracics while improving lateral mobility.

This is particularly important where saddle fit has been a major contributor to the problem. I have frequently found that in these cases,correction will take longer to achieve, as the debilitating effects of poor saddle fit (especially long-standing issues) can long outlast the change to a new, better-fitting saddle. In bodywork terms, the hypertrophic M. spinalis cervicis is often the last affected muscle to let go.

It’s as if M. spinalis cervicis is the emergency worker who will not leave until everyone else is safe.

Bodywork Notes

I am fortunate, in that my modalities enable the gentle release of joints through a non-invasive, neuromuscular approach. The responses I’ve had from horses when M. spinalis cervicis et thoracis has been addressed in isolation have been hugely informative.

Appendix: Spinalis in the Textbooks

I’m going to add Spinalis references to this post on a regular basis, as I come across them. It’s interesting to see how much, or how little, the muscle is referenced in various textbooks.

This image, from Equine Back Pathology, ed. F Henson 2009, shows acute atrophy of M. longissimus dorsi due to neurological damage. It’s still possible to see the raised attachment/origin of M. spinalis cervicis et thoracis – the highlighting is mine. Spinalis does not appear in the book’s index. (added 23 Dec 2016)

I have also altered this image, in order to show M. spinalis cervicis more clearly. This is Fig 2.16 from Colour Atlas of Veterinary Anatomy Vol 2, The Horse, R Ashdown and S Done. Spinalis cervicis is within the bounded area and it’s possible to see how it overlies the lamellar part of the nuchal ligament, lamellar portion. (added 23 Dec 2016)

The muscle is tinted green in this image from Sisson and Grossman’s The Anatomy of Domestic Animals, Volume 1, fifth edition 1975. Here, it is labelled Spinalis et semi-spinalis cervicis. This anatomical figure is credited to an earlier text, Ellenberger and Baum, 1908. (added 23 Dec 2016)

James Roony dedicates two pages to the ‘suspension bridge’ theory of the vertebral column in The Lame Horse (1988). His interest is in M. spinalis dorsii section of the muscle and its effect behind the withers, in conjunction with M. longissimus dorsii. (added 4 Jan 2017)

Master Saddler Jochen Schleese refers to M. spinalis dorsi and its function in stabilizing the withers in Suffering in Silence, his passionate book about saddle fitting from 2014. “This muscle area is especially prone to significant development – especially with jumpers – because it is continually contracted to accommodate the shock of landing”. The surface area of the muscle is indicated in the anatomical figure, reproduced here. (added 23 Dec 2016)

In his seminal text addressing issues of modern dressage training, Tug of War, 2007, Gerd Heuschmann includes M. spinalis cervicis in the triangle formed by the rear of the rear of the cervical spine, the withers, and the shoulder blades, “… an extensive connection between the head-neck axis and the truck… it explains how the position and length of the horse’s neck directly affects the biomechanics of the back.” (added 31 Dec 2016)

The ex-racehorse: a huge heart, a strong work ethic, great athleticism, wonderful sensitivity… and, potentially, a host of physical issues. Are you able to identify the problems so often present in these superb equine athletes?

A sports career can be tough on the body, as any committed athlete will admit. No matter how successful the athlete, the wear and tear and dings and dents will just keep on coming. It’s an inevitable consequence of making the body work at its outer limits of strength, speed and endurance: there are going to be times when the body just can’t make it or just can’t take the pressure. And that doesn’t count the spills and collisions that happen along the way. The same is as true for any top athlete as for any trainee who doesn’t make it past the foothills of success. And the same is definitely as true for racehorses as for any human Olympiad.

As in any sport, there are things that are done well, and things that are not done so well. Informed training and misinformed. Well judged and misjudged. Just as in the rest of the equine world.

Some thoroughbreds come out of the racing industry in fine fettle and have splendid second athletic careers in high end competition. Many have lower level issues that come right with some rehabilitation, leaving them suited to successful but less demanding careers. Others may be more suited to recreational homes, where life is one long pleasurable trail ride.

Unfortunately, many thoroughbreds with moderate problems land up in homes with people who are quite unaware of their horses’ issues.

What would you look for when buying an ex-racehorse?

When working with clients, I see a range of issues that come up again and again in ex-racehorses. I also see plenty of unsuspecting owners who didn’t know what they were buying at the time.

There’s a huge amount of love around, but the horse is often showing discomfort or pain, and the owner is only just realizing that (a) their horse may not be able to participate in the activities they’d hoped to experience together, and (b) getting the horse to a point when they can deal with these issues may cost considerably more than the horse did upon purchase.

It’s a sad situation. I believe that when looking at ex-racehorses, even those that have already had a couple of non-racing owners, you could do a lot worse than check for the physical issues listed here. Even better, get a vet to check the horse… but even then, you could run through this checklist before getting the vet in.

There’s functional and not-so-functional when it comes to ex-racehorses

Not all the physical issues are deal-breakers, of course. A horse can have one or two and still be able to function perfectly well (although if it’s straight out of racing, some rehabilitative work is going to be necessary). A big part of your buying decision will come down to:

the number of issues you can identify,

the severity of those issues,

what has already been done to assist the horse with those issues,

how much they will affect the kind of riding you wish to do, and

whether YOU are capable of providing the rehabilitation and retraining needed to support the horse through those problems – or if not, whether you can afford to pay somebody else who can.

The list that follows is by no means exhaustive – there are always more problems, especially as a combination of different problems can throw up further secondary issues. And I don’t go into hoofcare, which is worthy of another introductory article in its own right. However, it’s a major issue, so I’d recommend learning more about that too.

What I’ve decided to focus on here are problems that you can identify quickly and relatively easily. Most are visually identifiable. You can then get a more knowledgeable person to help you assess the horse or get a vetting completed before making a decision. Better still, do both.

1. Sacroiliac Damage – Not Whether it’s There, but is it Slight, Bad or Appalling?

This problem really is the number one, as every ex-racehorse has damage to the ligaments in this area. Depending on severity, there can be lesions that have healed, or lesions that have resulted in lasting weakness.

Frequently, when damage to the ligaments is severe, there’ll be further changes to the pelvis that are also visible. These may may or may not have the same root cause (see 2, below). One general rule, though, is that the horse won’t be symmetrical.

Major damage can rule out a future athletic career, while moderate damage may require rehabilitative work to strengthen the back and prepare the horse for future work. Minor damage isn’t necessarily an issue once the ligaments have healed.

Check for: asymmetry of the tuber sacrales (the two bony ‘pins’ of the croup), with one side being more than 5mm higher than the other. The horse may walk with one side of the pelvis lifting higher than the other – a hip ‘hike’. The muscle development over the glutes on top of the hindquarters may be uneven. These horse are nearly always cagey about picking up a back foot – they’ll swiftly lift it really high and then lower it into position. The horse can also find it hard to stand square, instead standing with hind feet close together – one toe may be angled outwards. Always look for problems with the lumbar spine as well (see 3, below).

Click to Tweet this important point: “The Ex-Racehorse and Sacroiliac Damage – Not whether it’s there, but is it slight, bad or appalling?” www.thehorsesback.com/ex-racehorse-problems

2. The Pelvis Can Be Equine Ground Zero

As well as sacroiliac problems, ex-racehorses can have other structural damage to the pelvis. Some of it you can see, some of it you can’t. The most important thing to do is check the pelvis for overall symmetry. What you’re checking for isn’t just pelvic rotation, ie. one side being higher or further forward than the other, but also distortion.

In horses that have had heavy accidents at a young age, the pubic symphysis (the lower cartilaginous join between the pelvic halves, directly between the legs) hasn’t formed properly. The pelvis may be forced wider due to impact or stress, and this part never joins.

What problems does this cause? With a severely distorted pelvis, a horse can’t work equally well on both reins and may not be able to canter at all on one rein. These horses also have a higher risk of having hidden stress fractures – hairline fractures that can worsen after a further fall or trauma later in life.

Indeed, make sure that all the pelvic ‘bony landmarks’ – the point of hip, point of buttock, croup – are actually present. Sometimes fractures lead to ‘knocked down hips’ or one tuber sacral may have dropped due to a fracture of the pelvic wing.

Check for: Pelvic symmetry, by checking the positions of the bony landmarks. If you know the horse and it’s safe, stand on a box a few feet behind to take a look down the back of the squared up horse (if it can square up, that is). Otherwise, hold a mobile phone directly overhead to get a straight-down-the-back photo, ensuring it’s dead center. ALWAYS STAY IN A SAFE POSITION – CLIMB ON A FENCE TO LOOK, WHATEVER. JUST STAY SAFE.

3. Heading North, South, East or West… the Lumbar Spine

If you’ve found any sacroiliac or pelvic issues, you’ll probably find problems in the lumbar spine too. Lateral imbalance in the pelvis will, more often than not, rotate the lumbar spine to one side or the other. Lumbar issues can also be found all on their own.

A long-term rotated lumbar spine will usually have some fusion between the vertebrae, and/or overriding dorsal processes (the part of the vertebrae you can feel). Fused areas are painful for the horse while they’re happening, and OK once the fusion is complete. But if fusion cracks, it can once more be extremely painful. Many horses compete just fine with some fusion, but if it’s severe, there’ll be problems with flexion, both vertical and lateral.

Check for:Use your hand to check the lumbar spine for the ‘lumps and bumps’ that can indicate overriding processes. Looking from the side, is the lumbar spine raised – ie, a roached back? This will usually tilt the pelvis back if it’s a longer term problem. If the pelvis is tilted forward, you’ll find there’s often a longer dip in front of the croup – the sacrolumbar gap is larger than normal.

4. Knee Bones: Take a Bag of Chicklets and Shake Them Up

Or so said Tom Ivers, one of the original equine sports therapy experts and a racing trainer to boot. Equine knees are delicate and complex, with many small bones (carpals), and undergo a lot of stress in a racing career.

Problems such as slab fractures and bone chips in the carpal bones happen due to over-extension (when the joint is bent back slightly) at high speed, or from constant loading on the same bend. Then there are more complex fractures, when the carpal bones break into more than two segments.

Check for: Puffiness around the joint, especially in front, due to previous swelling in the joint capsule. Old bone chips and slab fractures may have been dealt with at the time, but there can be lasting damage within the joint that leads to osteoarthritis (carpitis) later on.

5. The Stresses Left by Sore Shins

An ex-racehorse may have had an episode of sore shins in its early career. This is stress to the periosteum (the soft surface layer over the bone) caused by concussion – the body’s response is to lay down extra calcium to strengthen the bone. The bone recovers, but anywhere there’s been remodeling, there’s weakness in the bone.

If it’s severe, there may be an undiagnosed stress fracture that can go catastrophic under high pressure at a future date.

Check for:a curvature on the front of the cannon, which indicates that the problem was bad for heavy remodeling to occur.

6. Tendons, Tendons and More Damaged Tendons

Injuries to flexor tendons are extremely common amongst racehorses, with the deep digital flexor tendon and superficial digital flexor tendon being the most affected. These can be relatively minor lesions, which heal up quite nicely, to more serious ruptures that end a racing career.

There is always a risk of re-injury due to the weakness, and in serious cases, a second rupture could be catastrophic. It often depends on the quality of treatment and length of rest given at the time, as well as re-conditioning before returning to work.

Check for:a thicker area of the tendons indicates an old injury that has healed, while a curvature along the length of the tendon is a classic ‘bowed tendon’, sign of a far more serious injury.

7. Small but Vital: Fractures in the Fetlocks

Fetlocks are vulnerable due to hyper-extension, when the back of the fetlock comes too close to the ground when all the weight is borne on one foreleg at high speeds. Extremely high forces occur at the back of the fetlock and pastern as the horse lands the forefoot. Poor hoofcare, in the form of ‘low heel, long toe’ imbalance, also plays a significant part in this.

With fractures, the big, big issue is the type and location. A damaged sesamoid (the two small bones at the back of the fetlocks are the sesamoids)can play havoc with the vital suspensory ligament. So if you see signs of a problem, you’ll always need to know more, and that will usually mean involving a vet.

Check for:Sesamoid fractures will show up as ‘over-rounded’ or ‘apple shaped’ fetlocks, where swelling from an old injury has disrupted the joint capsule and/or extra calcium has formed around a restricted joint. Are the fetlocks of the forelegs the same size and shape? If one joint is larger and rounder, or if the ligament at the back of the foot feels thicker, with puffiness above the back of the fetlock, be suspicious.

8. The Stifles Cop It, Nearly Every Time

There are numerous causes for stifle issues in ex-racehorses, but you can take the view that if there’s a problem anywhere in the hindquarters, the stifle usually suffers. This includes any pelvic imbalance that leads to unequal loading of the hind limbs, never mind the forces of running on a unilateral bend…

Then there are the rotational twists that can happen in collisions and on bad ground. There are so many ligaments around this complex double joint that it really isn’t hard for it to get compromised.

Check for:A regular click as a hind leg starts to swing forward. This is the patellar momentarily catching, which can happens due to the lateral imbalance (causing misalignment in the femeropatellar joint). Other signs are visual: distension (swelling) of the joint may be visible from the side-on view, or from the front looking back towards the tail, depending on which part of the joint has been affected (femeropatellar or femerotibial).

9. Bringing up the Rear: Hocks Are Vulnerable Too

The hock comes under major stress due to being so involved in providing propulsive power in the gallop. As a major hinge joint, it is central to jumping out of starting gates/barriers, when it’s subject to the load of almost the entire horse. In the gallop, it must alternate between being compressed to absorb concussion, being rigid to build energy, and then extending fully to dispel energy and move the horse forwards.

Frequently, it’s doing this while subject to uneven loading on a bend. Then there are the unplanned twists and traumas. Well-conformed hocks may deal with this pretty well, but over-straight hocks and ‘cow hocks’ mean that the joint is less able to withstand high levels of work. It’s common for DJD to develop in the lower bones of the joint, especially on the side that’s on the inside of the bend the horse raced in.

Check for: look for puffiness on the face of the joint. Also look for bog spavins – these are specific fluid bumps on the front of the joint, which indicate underlying issues. Bone spavins are their bony equivalents, being hard bumps lower on the face of the joint, which indicate the presence of established DJD (arthritis). Also, listen for a crunching noise or a crack when the hind foot is lifted.

10. A Crash and Bang on the Shoulder

Racehorses can experience awkward impacts at the base of the neck, above the point of the shoulder. It can happen when bunched-up horses collide or run against railings, during a fall, or through everyday routine, such as a severe knock against a stable door. One outcome can be damage to the supraspinous nerve, which runs over the face of the shoulder blade (scapula).

When damaged, this can lead to wasting or even paralysis of the muscles over the shoulder blade itself, which is a problem, because these muscles stabilise the shoulder joint. This condition is known as ‘sweeney’. Mild cases usually recover, but more severe cases can be left with permanently wasted muscles. With reduced function in one shoulder and a shortened stride, the horse won’t be suited to demanding sports.

Check for:a lack of muscle over the shoulder blade itself. This is more than just tight muscles – the spine of the shoulder blade will be visually obvious and easy to identify through touch.

And There’s More… There’s Always More

It’s hard to know where to stop with an article like this, but I hope this is a good start when it comes to assessing a horse. You may be thinking that many of the problems are those you should check for in any new horse purchase – and you’d be right. However, anyone who works regularly with ex-racehorses will recognize that there are certain sets of issues that come with these former athletes.

What I haven’t covered: neck issues are common (calcification at the top of the nuchal ligament, misshapen atlas and atlanto-occiptal junction, etc), hidden stress fractures (radius and tibia are most common, but also the scapula… and others), the fractured ribs that come with sideways impacts in a race, misalignment through C6-T4, and quite a few more… but all are harder for the non-professional to assess.

Other information is more of interest to people working in the field. For this reason, I’m adding some links below. Please feel free to mention your own in the Comments…

To finish off, here are two horses that raced in Australia, where it’s common to train horses at the very racetrack where they run most of their races. In the state of NSW, the horses run clockwise (the bay), while in the state of Victoria, they run anti-clockwise (the chestnut). A view straight down the ‘unstraight’ spine can tell you so much!

Sometimes, a person from outside a profession successfully identifies something that has been unnoticed, overlooked or wrongly assessed for a long, long time. Coming from another direction, they see something that has been hidden in plain sight, simply because nobody looked there before.

Take amateur astronomers. They’re particularly well known for rocking the scientific community. In 2009, Australian Anthony Wesley discovered a visible scar left by a comet or meteoroid that had slammed into Jupiter, and we’ve all heard about Mr and Mrs Shoemaker and their neighbor Mr Levy and the comet they discovered in 1993.

Unusually, the astronomy community is able to recognize that while professionals have more technical background to analyze data, amateurs still play an important role in collecting it.

You might think that there’s no new data to be collected about equine pathologies, because every condition that can affect a horse, certainly above the level of microbiology, must already have been charted, mapped, researched and thoroughly understood. But, in the words of the song, it ain’t necessarily so.

Sometimes, all it needs is for someone else to be looking. And if that someone is looking with a rather different set of eyes or from a slightly different direction to the conventional scientific community, some rather remarkable results can come about.

If you’re looking for a different set of eyes for equine musculoskeletal pathologies, they don’t come much sharper than those of Sharon May-Davis. Few people have the razor sharp eye she has for a hidden pathology or condition in the horse.

She’s held in high esteem by riders in the sporting fields, because as an equine therapist, she has managed elite equine athletes at State, National and Olympic levels in 7 different disciplines including the recognized FEI ones such as eventing, dressage, showjumping and endurance. This has been accompanied by her extensive experience in the Australian and Japanese racing industries.

Sharon, seated, teaching biomechanics, Sept 2013

Sharon is also a biomechanics expert, a university lecturer in equine therapies and anatomy, and – significantly – a practical anatomist.

She has been conducting private equine autopsies for many years – it’s not for nothing that she’s been labeled The Bone Lady and Equine CSI. She also uses these 2-3 day dissection workshops to teach equine professionals and horse owners more about how their horses move and the damage their bodies can incur as a result of breeding, illness, injury or work.

She has been dissecting for personal research for over 20 years and professionally for 14 years. In fact, she now conducts up to 15 professional dissections per year – that’s a total of around 300 dissections so far.

Sharon is the first to state that she isn’t a vet and doesn’t hold a doctorate, but as a practicing equine scientist, researcher and practitioner, she is uniquely placed to provide a source of raw data that is all but unparalleled.

Evidence from the dissection table

Some years ago, Sharon noticed an unusual action in the elbow of horses. She mentioned this to qualified practitioners and was informed that this action was quite normal. Not convinced, she began videoing horses prior to dissection and, within a short period of time, was able to match this action to a change in the elbow.

Humerus, radius and ulna, showing damage to cartilage

Not to beat around the bush, it’s an unusual form of degeneration in the horse’s elbow joint that involves all three bones. It’s a form of osteoarthritis that strikes the humeroradial joint and the ulna, causing deep and dramatic gouges into the cartilage, and eventually eroding bone.

When the joint is opened up, blood is frequently found in the synovial fluid (haemarthrosis). The fluid also displays decreased viscosity.

This is more than a little bit odd, as arthritis of the elbow is supposed to be rare in the horse.

Yet Sharon has found it to be present in numerous horses that have been euthanized under veterinary supervision for completely unrelated reasons.

This equine arthritis is visible in the living horse

The vital connection from video to dissection has enabled Sharon to indicate the presence of the elbow osteoarthritis in the horses she had been treating as an equine therapist.

It’s easy to spot, being a noticeable jarring in the elbow as the horse moves downhill – a kind of double action – you can see it here. Significantly, it’s what can be termed a gait anomaly, rather than lameness.

Does it look familiar? It’s very likely that you’ve seen it in horses before and wondered what it was. The fact is that it’s so common, many people think it’s a normal action. It’s not. It’s a form of equine arthritis.

Sharon tells us she has seen the elbow problem in all types, breeds, sizes and ages of horses. Some affected horses have been elite dressage and eventing competitors. Interestingly, the problem is only presenting in ridden and driven horses.

If never worked, horses appear to remain forever free of this particular joint change.

Why the fuss – isn’t this just regular arthritis?

No. Arthritis of the horse’s elbow is considered to be rare in equine veterinary medicine.

How it should look: healthy radius and ulna (unridden horse)

The key to why it doesn’t often get diagnosed and is considered rare could be the absence of visible lameness. The arthritis identified by Sharon does not cause a distinctive lameness in the horse, although it does bring on a notable gait change, with the double step in the joint’s motion on the downhill.

Riders of such horses often just feel that their horse is a bit ‘off’, feeling a hesitation in the movement, but without being able to define the point of origin.

There are a couple more reasons why it’s not very visible: first, the action of the elbow is highly integrated with the overall shoulder action, and second, the massive triceps muscle has a further stabilizing effect on the joint.

Radius and ulna of ridden horse, showing cartilage wear and blood in joint

And even if the elbow is explored, the relatively tight joint space means that degenerative problems are rarely seen in diagnostic imaging, although inflammation can show up in thermographic images.

When, unusually, a problem has been recognized and vets have attempted a corticosteroid injection of the joint (which happens to be the most difficult joint to access), blood has been found to be present.

A closer look at Sharon’s findings

Sharon May-Davis first presented some of her findings into elbow arthritis at a conference in Australia in February 2013: the Bowker Lectures at the Australian College of Equine Podiatherapy. Presenting alongside Prof Robert Bowker and Dr Bruce Nock amongst others, she discussed the club foot in the horse, and noted how the elbow degeneration she observes on the dissection table is always worse in the forelimb with the more upright hoof.

If the condition is bilaterally present, it unfortunately appears worse on the side with the slightly upright or higher hoof. What’s more, and according to Sharon, this also applies to the limb where an inferior check ligament desmotomy (surgery undertaken with the aim of correcting an upright hoof) has taken place and the ligament has later reconnected.

She has, as already mentioned, since established that it can occur in any ridden or driven horse. Here, she describes the problem in her own words.

“The action looks like a slip and or clunk into the shoulder or a shudder or a sliding / slipping action. It depends upon your perspective. The actual change in the action begins when the foreleg is in the ‘Stance Phase’ during the stride as the limb goes into the posterior phase of the stride. It is more obvious going down a hill.

“So far, 100% of ridden horses exhibit this condition to a varying degree (under dissection). Horses not ridden and with no abnormalities do not exhibit this condition (under dissection). Horses in harness also exhibit this condition.

“What does the joint look like? There appears under dissection to be substantial degradation in the cartilage of the humerus, radius and ulna.

“Most horses appear to handle this condition and continue with a normal life if not pushed to extremes. Although this sounds career-ending, in fact it is not. Once the horse gets through the worst of the wear pattern they re-settle in the joint and continue on with work.

“High level competitors require joint support to help sustain the elbow and other joints that may compensate for the change in action.

“Horses that jump are more inclined to land with straighter forelimbs. Be mindful that jumping and downhill work could possibly make the condition worse.

“Riders often feel instability in the horse’s forelimbs when traveling downhill and some even question the horse’s proprioception.

“Bodyworkers massaging the triceps (particularly the lateral triceps) actually exacerbate the condition as the massage releases the cast-like formation that this muscle provides.”

More research is needed, but so is support

Humerus and radial bones showing arthritic wear

Despite finding and documenting a huge number of dissection cases involving this particular issue, all unaided and unfunded by outside bodies, Sharon has consistently met with brick walls and skeptical responses when she has put the information forward to relevant authorities.

She isn’t looking for funding (although she obviously wouldn’t say no), but would like to have this research taken up for the benefit of all ridden and driven horses. The sooner the problem is recognized and investigated, the sooner that episodic pain in the horse can be recognized, with appropriate joint support or rest given where appropriate.

And the sooner we can all learn more in our great drive towards improved equine health, the better. As Sharon says,

“In truth, we are still in the dark. Seeing it is one thing, analyzing it and providing a preventative program is something totally different.”

Showjumped up to 10 years. Competed in dressage from 11 years. Retired from riding at around 20 years due to unresolved lameness.

Here is a video of this horse, showing severe elbow degeneration (as well as other pathologies):

And here are images from the dissection table. Note the bruised and bloody cartilage of the radius, ulna and humerus. Also, the droplets of synovial fluid are discolored, being a very unhealthy reddish brown.

More Information

Sharon May-Davis, B. App. Sc. (Equine), M. App. Sc. (Ag and Rural), ACHM, EBW, EMR was the Equine Therapist for the Modern Pentathlon Horses and the Australian Reining Team at the Sydney 2000 Olympics. She has worked with the Australian Champion from seven differing disciplines and has a particular interest in researching the musculoskeletal system. She also conducts clinics and seminars in relation to her work and regularly presents in the Northern and Southern hemisphere.

Meanwhile, Sharon is answering questions in the comments section, below. Discussion is positively welcomed, so please feel free to ask questions or share experiences. Sharon will drop in to answer them if you do.

Not long ago, I was having a quiet think about the reasons that people buy saddles that so obviously don’t fit their horses. This is a regular spell of head-scratching that occurs when I’ve worked on a few horses with back and postural issues stemming from saddle misfit.

Now, in my view, a saddle fit session is a pretty critical part of buying a saddle. It goes without saying, surely, that there’s a living, breathing horse out there in the paddock or stable and that the new saddle needs to fit onto his back – and that this suitability really does need to be established before the saddle is purchased.

Yet, many people still buy a saddle and only afterwards try to establish whether it will fit their horse or not. It’s all a bit of a gamble – not only with their money, but with their horses’ comfort and back health.

What on earth is going on here?

Good question. Either people are genuinely unaware of the reasons for fitting saddles, or they do know but are marching to a different, louder drumbeat when they go shopping.

To make more sense of this, I decided to apply the psychology of consumer buying behavior. At the simplest level, there are five stages involved in a purchase: need recognition(we feel the need for a new saddle), product research(we learn what’s out there), evaluation(we consider everything learned through our research), purchase decision(we carefully select the most suitable saddle),and post-purchase behavior(we react positively or negatively to our choice).

Well, how tidy is that? Too tidy, maybe. The problem is that we all behave erratically when shopping, being influenced by our personal biases. These are preferences, beliefs and thought processes that hold up our personal view of the world – and our illusions. Biased behavior includes:

Cherry-picking information by being selective over what we see, hear and read,

Yielding to peer pressure,

Favoring someone’s viewpoint because we like them (whether we know them or not – take celebrity endorsement),

Supporting our self-image (actually how we think other people see us),and

Being totally inconsistent in our behavior, just because we do that.

We’re none of us exempt from this. Being emotionally charged, biases are very motivating. What happens is that they can leapfrog us from need recognition straight to purchase decision, making us ignore the research and evaluation findings or leave them out altogether. (And this forms the basis of every advert you’re ever likely to look at.)

10 emotional saddle-buying decisions

Here are 10 ways that you can succumb to biases that skew your saddle purchase decisions.

1. Your instructor or trainer uses thatsaddle

“I could be that good too…where’s my credit card?”

Whoah… this could cause some shouting, but instructors, trainers and clinicians don’t always know all there is to know about saddle fit, even though they know HUGE amounts about riding and training.

No offence meant, honestly, but some riding instructors give their students terrible advice about saddles. They say one fits, when it doesn’t. Horse owners just follow this well-meant advice, because they really believe in and admire their instructor.

Some trainers and clinicians even use a favorite saddle on all their own and their clients’ horses. It suits the rider, so… Some of these cause damage and the clients often don’t realise until someone else points it out at a later date. (There’s a variation on this one, too: attend clinic or do course, then buy saddle. No further comment.)

2. Your knowledgeable friend owns that saddle

A lot of horse-related knowledge is passed between friends. When it’s good, it’s good, but when it’s bad, it can be very bad.

No matter how much you like your friend, there’s a high chance that their physique and their horse’s is likely to be different to yours. And your friend will very likely ride differently too. These three points are frequently overlooked.

3. There’s a local saddle maker in town who makes that saddle

Saddler who learned from his father, who learned from… Photo (c)Nicola Valley Museum

He lives close by and tells the local horse community all about what he does and what he makes. He’s knowledgeable, he loves his work and, dang it, he’s such a nice guy.

It’s possible, just possible, that he may know more about producing beautiful hand-crafted saddles than equine anatomy and biomechanics, having learned more from his father and other craftsmen than from modern schools of equine thought.

And, obvious as it sounds, there’s a difference between a saddle-maker and a saddle-fitter, although there are definitely plenty of saddle-makers who are also great saddle-fitters. But at small town level it can, and does, go either way. (You can probably tell I’m trying not to offend anyone here.)

Can the buyer tell the difference? Frequently not, as so many people buy an expensive, custom-made saddle that doesn’t fit, but which can’t then be returned. (If this isn’t the case with your locally made saddle, then brilliant – I’m genuinely pleased for you.)

4. That saddle is named after a famous rider

A famous rider’s name is on the saddle, but it still doesn’t fit

There are many saddles out there named after a top-of-their-game rider – it’s celebrity endorsement with bells on.

It’s a funny thing how what works for them makes that style of saddle suitable for hundreds of thousands of other riders and their horses, of all shapes and sizes. And the buyer’s riding will improve to an unfathomable degree… won’t it?

Aspirational shopping aside, some of these saddles are amazingly good, but (no naming names now) not all of them are. This is particularly true if they’re occupying what we can call the ‘value end’ of the market.

5. Your friend with the same breed of horse as you has that saddle

This saddle fits all arabians – and look, it’s a bargain too!

Some people constantly draw parallels between their own horse and that of a friend or acquaintance who has a horse of the same breed. The prospective saddle buyer sees which saddle their friend has and decides it must be good for their horse too. This is so much the stronger if the owner is much admired or is winning in competition with that saddle.

Yes, breeds obviously have prevalent conformational traits. But it’s not a given, as horses – and their riders – can be very individual.

Images of dream-like perfection…

6. You’ve seen a stunning photo of that saddle in a magazine

And it really was beautiful. The horse was beautiful, the saddle was beautiful, and the rider was stunningly beautiful. An image of dreamlike perfection… in an advert. It always works, doesn’t it? We’ll all look just like the stunner in the photo once you buy the saddle. No, I don’t think so either.

7. A forum regular recommends that saddle

We all know them and recognize them: the person who is very vocal on forums, being big in their own lunchtime with strongly held opinions. A queen bee, they hold forth at the center of a community of regulars who mutually reinforce one anothers views.

To the less informed reader, this verbiage may sound like unassailable fact. So when the queen bee says a certain saddle is the best and how it’s right for certain horses, her view may be perceived as being expert opinion. (Hey, she may indeed be right, but not above and beyond someone who is standing look and assessing fit on actual, living horse – with a rider on board.)

8. When you were a kid, everyone craved that saddle

Big brand saddle – but the design has had its day

Times change, the knowledge-base grows and designs evolve. The industry moves on (although some companies don’t) and what was great back then may not be so now. Brand names rely on consumer loyalty, but over long periods of time your loyalty may be misplaced. Formerly great brands may now be merely good, which is OK if the price reflects that change, but…

Have you noticed that people will buy used, 25-year-old spine-pinchers just because they were made by that company?

9. Your horse went better when you tried out that saddle

What? Surely this one’s a no-brainer? You’ve borrowed a saddle and your horse went better in it than in your old saddle, which was causing problems – that means the borrowed saddle is a good fit, doesn’t it?

Nope. It’s a sure-fire indicator that your horse is showing relief at not experiencing the same old pokes and pressure points when ridden, because at last somebody has taken the offending piece of leatherwork off his or her back. What we aren’t seeing at this stage are the new problems that may emerge from this replacement saddle that may not fit, but in a different way.

It’s like repetitive strain injury – it can take time for signs of problems to become visible (although in endurance riding, problems can show up within a single day’s ride.)

10. You’ve never seen a better price attached to that saddle

In an online world, we’ve never been more able to shop around for that super-bargain. And when we find it, it’s all so much easier to ignore any possible shortcomings. This is even more so when time pressure is involved, for instance in an online auction.

Try to bring in reason over emotion

Oh I know, it’s hard to do. We’re never going to escape the emotional side of shopping, particularly with new – or new to us – saddles. The bigger the purchase, the more rewarding it’s likely to be.

Yet that’s all about us. Our horses are happily unaware of the thrill of shopping. To the horse, a saddle that fits will minimize the negative effects of bearing (our) weight on its back – while one that doesn’t fit won’t. We owe it to our horses to make informed and well-considered decisions.

I realize that it can be hard to know if you’ve got a good saddle fitter, but involving a trained professional in the research and evaluation stage of your buying decision will certainly decrease the chances of making a catastrophic error that will cause pain and damage to your horse.

Alternatively, in this online world where you can find those superb saddle bargains, hop onto YouTube and take look at some of the excellent videos posted by professional saddlers. It couldn’t be much easier.

Look on any ivermectin or moxidectin-based wormer packet and you’ll see a long list of parasites. Tucked in neatly at the end – it’s nearly always at the end – you’ll see the words Onchocerca Microfilariae, otherwise known as neck threadworms.

Also known as neck threadworms, these critters vary in length from 6cm to 30cm (think the length of a regular ruler). Astonishingly, they live in the horse’s nuchal ligament.

Yes, the nuchal ligament. It runs the full length of the neck, from poll to withers, with a flat ligament part connecting with the cervical vertebrae.

Apparently, most horses have Onchocerca. For many they’re not a problem, but some horses develop a reaction to their microscopic larvae (the microfilariae). This is known as Onchocerciasis. The horses become itchy, mostly around the head, neck, chest, shoulders and underside of the belly. That’s why owners often make the understandable assumption that their horse has Queensland itch or sweet itch.

A quick introduction to neck threadworms

Original article by Jane Clothier, posted on www.thehorsesback.com, June 2013. All text and photographs (c) Jane Clothier. No reproduction without permission. Links to this page are fine.

Onchocerca is what’s known as a parasitic filarial worm (nematode). One reason these worms get relatively little attention is that they never live in the intestines. The microscopic larval form live in the horse’s skin, mostly around the head, neck, shoulders, chest and underside of the belly. It is the adult worm that later makes its home in the nuchal ligament.

The problem is global and horses in most countries have been found to have this parasite. Unfortunately for those of us who keep horses in warmer, humid climates, it’s more frequent here. The biting insect that serves as a carrier is the Culicoides fly, which is also connected to Queensland Itch (aka Sweet Itch, Summer Itch, etc.).

It’s an unfortunate coincidence of environment that leads to many cases of neck threadworms being missed, because they’re assumed to be Itch.

Does your horse have “the itch” – or neck threadworms?

It’s a humdinger of a thought. If your horse is itchy, something different could be happening to what you think is happening.

Your horse has the ‘regular’ itch (ie, Queensland, sweet, whatever it’s called in your region) and are reacting to midge spit – and nothing else. (The point of this article certainly isn’t to try and say that all itch cases are due to neck threadworms. Just some.)

Your horse has neck threadworms and its inflammatory reaction to them has increased its sensitivity, so it’s now reacting to fly bites everywhere – in other words, Queensland/sweet itch has been triggered as a secondary response.

Your horse only has neck threadworms, in which case they’re probably rubbing along the mane and particularly the base of mane, around the neck and face, under the chest and down the ventral line (under the belly), but not on the tail head – or at least, relatively little.

Are you by any chance now thinking other horses you know? If so, they might be suffering from Onchocerciasis. There’s a lot of it about.

So how do we identify neck threadworms?

A pony with the Itch and neck threadworms. It’s Autumn and she’s stopped rubbing out her entire mane – it has grown back – but is still itching that tell-tale area in front of the withers. Her coat is raised in a temporary histamine reaction to the ivermectin wormer.

Neck threadworms have a distinctive life cycle, but as is so often the case, the problem presents in different ways, depending on the individual.

In my brumby Colo, it started with him scratching the underside of his neck on posts. That was about 3 months before I had an inkling it might be neck threadworms. How I wish I’d known what it was at that point, so that I could have nipped the problem in the bud…

I’ve also seen it manifest as a new, previously unseen itchy and scurfy patch on the lower part of the neck of a horse who’d never been itchy. And I’ve heard of a local horse who suddenly started furiously itching his face, bang in the middle of the forehead, to the point that it bled. He had never been itchy before.

These are the classic early signs, usually recognised by the owner only through miserable hindsight. Other signs include small lumps forming along the underside of the horse and on its neck and face, weeping spots, and a scaly crest to an area of the mane through rubbing.

The base of the mane, just in front of the withers, seems to be party central where neck threadworms are concerned.

,

The real nastiness of neck threadworms

The microscopic larvae can travel to the eye, although this is rare.

It just gets better: the larvae can travel to the horse’s eyes, where they can cause untold damage. This cheering sentence from Scott and Miller’s Equine Dermatology sums it up: “O. cervicalis microfilariae may also invade ocular tissues, where they may be associated with keratitis, uveitis, peripapillary choroidal sclerosis, and vitiligo of the bulbar conjunctiva of the lateral limbus.”

Oh heck. Nobody’s sure how common this is. All I know is that I don’t want to find out the hard way.

Consider this: in humans, a slightly different strain of Onchocerca infestation is known as River Blindness.

Please remember this detail when you’re deciding whether to worm for neck threadworms or not.

The very strange lifecycle of the neck threadworm

These worms have a complicated existence. They’re among the shapeshifters of the parasitic worm world, developing through several larval stages before reaching adulthood.

The first stage microfilariae live in the horse, close to the skin. Their numbers are highest in the spring and decrease to their lowest point in mid-winter. They live in clusters, which is why you may first notice patches of scurfy skin where the horse has started itching. This is a reaction to the dead or dying larvae.

Itching down the midline. Mine have itched neck and shoulders only – so far. (Photo courtesy of blog, Baba Yaga’s Mirror)

At this point, our good friends the culicoid flies make a contribution, by biting the horse and ingesting a good number of microfilariae along with blood. Within the fly, the larvae then develop through a further stage (or two). They are then deposited back into a horse when the flies bite. The flies can do this for an impressive 20 to 25 days after first hoovering up the larvae.

Back in a host horse, the larvae then make their way via the bloodstream to the connective tissue of the nuchal ligament, which runs along the crest of the neck. Here they moult and develop into adult worms. The adults live for around 10 years and in this time, the females release thousands of microfilariae (larvae) very year.

Original article by Jane Clothier, posted on www.thehorsesback.com, June 2013. All text and photographs (c) Jane Clothier. No reproduction without permission, sorry. Links to this page are fine.

No matter where the adult worms settle, the itchiness is caused by the microfilariae that aren’t lucky enough to be consumed by a fly and are instead left to die off.

The next part’s really not fair. The more the horse itches and breaks the skin, the more the flies will bite exactly where the microfilariae are located, before transporting them to the same or another horse, to start all over again.

Can we test for neck threadworms?

The microfilariae can be identified in the living horse through a biopsy of the nuchal ligament. Published veterinary research shows you won’t get any indication within 34 days of worming, so the timing is critical.

Worming with ivermectin can lead to weeping spots in the mane. These can be painful. This photo was taken after they’d cleared, leaving bald areas. Sometimes the hair grows back white.

A dose of ivermectin-based wormer is the quickest way to tell if your horse has them. If the microfilariae are present, the horse usually responds with intense itching – and I mean, manically intense, demented itching – around 48 to 72 hours after worming.

It may develop weeping, gunky spots at the base of the mane. (If you live in a paralysis tick area, it’s similar to the localised reaction you see in response to the ticks.) These are very specific spots around 1cm in diameter, with hair loss after they’ve erupted.

My brumby responded this way, rolling furiously and rubbing vigorously against posts. Unsurprisingly, he was also hard to handle for a few days. He was definitely sore at the base of the neck, where the weeping eruptions came out, and didn’t want to be touched there. I have to say that the scale of his reaction came as a shock to me, so take heed and be prepared with some soothing salves.

What can we do about adult neck threadworms?

Here’s the depressing answer: not much. But we can manage them.

The nuchal ligament runs from poll to wither and links with the vertebrae. Yellow = funicular part, home to neck threadworms. (Image copyright Sustainable Dressage.)

The adults live for 10-12 years and happily inhabit the nuchal ligament. What often happens is that the horse’s body throws down calcification around the adult worms in an attempt to isolate the foreign body. In some horses, you can feel a collection of pea-like bumps in the nuchal ligament. In the ones that I’ve checked, this was just in front of the withers.

The slightly better news it that the worms are so fine and the lumps so small that it doesn’t seem to affect the function of the ligament, which is tough and fundamentally taut anyway. However, I’ve not yet knowingly seen a horse with a long history of neck threadworms – I’d be interested in doing so.

Heavier calcification is usually most prevalent in horses in their late teens. It figures, as the adult wormers are older, and longer. Apparently they intertwine and live in small clumps. Mid-aged horses have mainly shown inflamed tissue around live parasites.

In horses less than 5yo, the parasites can be present but there’s relatively little immunological response. So if your horse has suddenly developed itchiness at the age of 5 or 6, you could be looking at the presence of this parasite.

Original article by Jane Clothier, posted on www.thehorsesback.com, June 2013. All text and photographs (c) Jane Clothier. No reproduction without permission, sorry. Links to this page are fine.

Managing the initial outbreak

Do you worm your horses? Do you want to reduce the itching at the cost of having to worm more? I know I do, but I realise that some people can’t abide the thought of chemical wormers, or their increased use. But here’s what you can do if you want to reduce that dreadful itching and virtually eliminate the possibility of eye damage.

Unfortunately, there’s no single recommended protocol for worming against neck threadworms, so you’re in fairly uncharted territory.

To address the initial outbreak, the advice ‘out in the field’ is to use a regular dosage of an ivermectin-based wormer, multiple times until symptoms subside. The recommended interval I’ve seen is a week, but do check with your *equine* vet first.

I’ve also read forum posts by US horse owners stating that a double dosage at fortnightly intervals is the most effective treatment. It’s usually around three doses, or until symptoms subside. One reason is that lower doses do not kill off enough larvae, allowing resistance to develop amongst those that remain. Wormers are certainly tested as safe at higher dosages, but again, horses are individuals, so always check with your *equine* vet first.

I’ve read that an injection of ivermectin can be more effective, with off-label use of a product such as Dectomax being recommended as the heavy artillery when all else has failed. Again, do check with your *equine* vet.

Some say that an ivermectin and praziquantelwormeris more effective. One small comfort is that these wormers are available in the lower price ranges. It’s a consideration, because if you’re worming multiple horses, this won’t be a cheap time. It may even be worth looking at the large bottles of liquid wormer used by studs for greater economy.

Published research has shown that moxidectin-based wormers are equally as effective in addressing the microfilariae (but don’t double-dose with this one – only with ivermectin). That’s good, as it means you can address the neck threadworms, while covering your horse for encysted strongyles too (ivermectin wormers don’t).

Whichever option you follow, it’s worth following this worming protocol with prebiotics, probiotics and ‘buffers’ such as aloe vera to support a healthy gut lining.

Reducing the larval population

After the initial worming, it’s a matter of management. What you’re trying to do is keep the numbers of microfilaraie low, so that the horse’s itching is reduced. Remember, most horses show little reaction, although the parasites are present. The aim has to be to bring them down to levels the horses’ systems can deal with, while taking other measures to boost the horses’ immune system.

Some vets say a single dose every 6-8 weeks during the fly season.

Others say every 3 months, timed in accordance with the larval lifecycle, which is 4 to 5 months.

In humid sub-tropical zones, where all parasite burdens are dramatically higher, I’ve heard of people doing it as frequently as once a month.

Beyond that, you’re back to the barrier treatments – fly rugs, lotions and potions to deflect the flies and to insulate the skin, lotions to soften the skin and heal the lesions, fly screens on shelters during the day, etc. And don’t forget about boosting your horse’s immune system generally through sound nutritional approaches.

And if we do nothing?

If we don’t address the problem one way or another, we have very itchy horses, for their entire lives.

Researchers say that the calcification in the ligaments has no effect, but you’ve got to wonder. There’s no guarantee that those scientists had a highly developed understanding of equine biomechanics. Maybe they did, but… who knows. A lot of the small amount of research available is over 20 years old and the knowledge base has since grown.

There’s a small but serious risk of damage to the eyes.

On the plus side, Onchocerciasis hasn’t been found to have any association with fistulous withers.

To recap…

Onchocerciasis is so often masked by the itch that awareness, even in the regions where it’s rife, is low.

And in those same regions, there are so many highly prevalent and deadly parasites – the worms that cause colic, that drag down the horse’s condition, that can kill through spontaneous mass emergence from encysted larval stages – that the neck threadworm larvae simply doesn’t get much of a look-in.

To repeat, I’m not saying that all cases of itch are neck threadworms. Just that these parasites may be involved and can be a contributory factor in a heightened immunological response that leads to Queensland itch (or sweet itch, or whatever you know it as).

However, some horses definitely have neck threadworms. The earlier we can identify and manage it, the better.

We can’t eliminate the neck threadworms, but we can certainly manage the effects and make our horses’ lives more comfortable.

Well? It’s not such a daft question. Many therapists double up for horse and rider and some even work on riders while they’re on their horses.

There’s a saying that holds that how we treat our animals reflects how humane we are as a society. Bringing that down to a more individual level, the nature of the care we give to our animals often mirrors the care that we arrange for ourselves.

For horses and riders, that has certainly changed over the years – and it’s still changing.

And it’s getting more complicated.

Have you heard people saying how simple it used to be keep a horse? Maybe you’ve said it yourself, while giving a wry smile. You’ll even hear some people saying that they never did ‘all these things’ for their horses and that their horses never had anything wrong. (I find there’s often an older lady at the back of a saddle fit demo who’ll come out with that line.)

Well, until around the 1980s, it was much simpler. In just the same way that many people would see a doctor and a dentist and very occasionally a specialist such as a chiropractor, most domestic horses would only ever see a vet and a farrier. Just occasionally an owner might call in the equine chiropractor, but it certainly wasn’t a routine practice.

And were the horses physically OK ?

There’s no doubt that some of them were. Some always are, no matter what life throws at them.

But I imagine a lot were running around holding it together, busily hiding their problems, as horses do. As an evolutionary food source, they’re very good at hiding their weaknesses, having no wish to be first option on the menu at the Wild Dog Diner.

When I hear people pointing out the OK-ness of horses in decades past, my response is that it’s unlikely many people were checking horses’ backs in those days. My experience is that considerable numbers of present-day owners can’t tell if their horse has a sore back, so what were the chances of the ‘average owner’ spotting it then?

Admittedly, from the saddle fit point of view, it’s a discussion that can go on and on, taking in types of riding activities and styles, breed variation, changing use of horses … there are many reasons why fitting has become more complex over the years. But I’ll still firmly refute the notion that horses didn’t have problems.

But let’s return to modern day therapists.

If you use any horse therapist at all, you’ll know that there’s a directory full of professions to choose from. This really does reflect how things are in our own world of personal physical care. Instead of just going to a doctor, many of us listen to the advice of other professionals as well. Some people take complementary practitioners’ advice ahead of their doctors’, the reasoning being that it’s specialist knowledge. Other people leave out the doctor altogether. It’s all a matter of personal choice.

And there’s a thing – we do have the luxury of such choices now.

We’re more aware of our needs – and those of our horses too. The internet has helped us to identify problem areas and solutions, although there’s a lot of inaccuracy and outright misinformation out there, too.

That’s why we ask our friends what they think and tell our friends what we think.

And when we research online, we ask our online acquaintances too (although it’s as well to be cautious of new online friends, at least until we know more about them.)

Now there are online courses for us to develop our knowledge too. We can gain qualifications without leaving our front rooms. One outcome is that many of us take more aspects of horse care upon ourselves – hoof trimming, massage or nutrition, for example. And many of us are more aware of when we need to call in a professional, because we’re becoming more accomplished at reading the signs of need in our horses.

Which brings me to the point …

I’d like to open a bigger window into the world of not just bodywork for horses, but saddle fit as well. This is not to do away with professional saddle fitters or therapists (or, heaven forbid, vets), but to help horse owners recognize when a problem is present or emerging. That really is the key to knowing when to call in a professional.

Lots of physical problems are obvious when you have an idea what to look for… it’s not that hard.

And I reckon that maybe 8 out of 10 saddle fit problems come down to a few basic issues. Again, in themselves they’re quite easy to figure out. When the basics are easy to learn, why not talk about them? I reckon that if a bunch of the most obvious problems can be addressed on pages such as this, it has to be a good thing.

What do you think?

If you’ve enjoyed reading this, sign up here to receive a short email each time something new is posted. No spam, no hassle – and that’s a promise!